Reversible rotary tool holder



v June 11, 1957 Filed June 24, 1953 ALFREDEEN REVERSIBLE ROTARY TOOL HOLDER 2 Sheets-Sheet 1 Fig1 I 1o 66 a 28 /so 14 r W, :1 11( 3g 56 9 w 62 4e 3 so a -16 4a 44 as 52 40 5Q '2 7 d baa -78 8 9s g3 72 88 v 92 5g as June 11, 1957 r u. A. ALFREDEEN 2,795,145

REVERSIBLE ROTARY TOOL HOLDER Filed June 24, 1953 '2 Sheets-Sheet 2 v Fig 3 M 2 48 38 ,45 44W I y United States Patent REVERSIBLE ROTARY TOOL HOLDER Uno Allan Alfredeen,Saltsjo-Duvnas, Sweden, assignor to Aktieholaget Svenska Precisionsverktyg, Nacka,

Sweden, a joint-stock company of Sweden Application June 24, 1953, Serial No. 363,883 Claims priority, application Sweden July 1, 1952 9 Claims. (Cl. 74--205) This invention relates to a reversible rotary tool holder comprising a driving component and a driven component as well as force transmitting members interposed therebetween and including coupling members for direct drive and intermediate members for reverse drive rotatably disposed in a rotationally stationary retaining member and running in confronting grooves forming races and located on the driving component and an annular member.

One object of the invention is to provide a tool holder of the type set forth and in particular a screw cutting device having means ensuring besides the reversibility an exact operation of the tool and in particular cutting of an exact thread independent of the skill of the operator.

Further objects and advantages of the invention will be apparent from the fol-lowing description considered in connection with the accompanying drawings, which form part of this disclosure and of which:

Fig. l is a longitudinal sectional view in two parts taken on line II of Fig. 2 of a thread cutting device constructed according to the invent-ion, part of the driving spindle of the device being separately shown to condense the figure.

:Fig. 2 is a partly sectional view of the apparatus taken on line lI lI of Fig. 1 and showing an annular member constituting part of the driving component of the device.

Fig. 3 is a sectional view taken on line IIII II of Fig. 2 of the annular member presented in Fig. 2.

Fig. 4 is an axial section through a further annular member belonging to said driving component.

Referring to the drawings, designates a spindle centrally secured in the front wall 14 of a downwardly open hood 16 forming a hollow body of rotation. The fixing place is on a tubular "socket 1'8 projecting from the front wall and having a smaller diameter than that of the hood 16. Said socket is provided with an outer thread 20 fitting an inner thread of a central bore in the front wall 22 of a further hood 24. The latter hood has an inner diameter larger than "the outer diameter of the first-mentioned hood 16 and is thus .adapted when threaded down on the socket 18 to overlap the upper end of the hood 16. immediately below the front wall 22 of the hood 24 is disposed a loose annular member 26 carrying a number of guide pins 28 fixed thereon in spaced relation to one another and engaging together with helical springs surrounding said pin bores 32 provided in an inwardly projecting and thicker portion 34 of the front wall 14 of the hood 16. Said thicker portion projects also for a short distance alongside the inner cylindrical wall of the hood 16 and leaves open a likewise cylindrical space 36 housing an annular or sleeve shaped member 38 which at its base merges into an outwardly projecting annular flange 40 extending towards and adjacent to the interior wall of the hood 16 along a lower face 42 of the portion 34. The upper surface of said flange is provided with a plurality of spherically curved recesses 44 spaced apart in conformity with the spacing of the bores 32. Said bores extend entirely through the portion 34 and house in their lower ends,

and having an arcuate cross-sectional profile. The 'annu lar or sleeve-shaped member 38 has on its outer cylindrical wall a circumferential groove 48 facing axcorrespondingly shaped groove 50 provided on the interior wall of part 54 bounding the space 3.6. In these confronting races are located balls introduced through an opening in the part 54 which upon introduction of said balls has been sealed by plugs 56. The balls 52 thus fix the hood 16 and the member '38 in the axial direction, but permit them to rotate freely, relative to one another. For the transmission of the torque moment to be transmitted under direct drive to the chuck seat 58 from the driving spindle 10 by way of the hood 16, .the balls 46 and the annular member 38, the inner bore 59 of this latter memher in the embodiment illustrated is provided'with axially projecting shoulders 60 located' diametrically opposite one another and chamfered at their lower ends. Said shoulders terminate some distance from the underface of the annular flange 44) and are adapted 'to abut, during rotation of the member 38, against two rollers 62 mounted in a bush 64 traversing a head 66 disposed on the chuck spindle.

Below the annular or sleeve-shaped member 38 is disposed a further annular member 68 composed in the embodiment illustrated by two annular parts 70, 72 each of them with the outward face forming a race denoted by 74 and 76, respectively. :Said races .are intended to locate balls 78 mounted in two superimposed rows within a retaining member 80 and besides adapted to run on one of two further races 82 provided on the inner wall of the hood 16. The retaining member :80 carries an arm 81 projecting outside the hood 16 and intended to keep this latter rotationally stationary relative to the rotatable members of the device. The races of both the annular member 68 andthe hood may have an arcuate cross-sectional profile composed of straight lines or a profile composed of straight lines and arcs. As already stated, the member 6 8 is constituted by two parts of which one denoted by 70 has the shape of a sleeve the inner cylindricalwall of which carries two axially extending shoulders 84 located diametrically opposite one another and chamfered at their upper ends, said shoulders beginning at a distance from the top end of the sleeve and extending downwardly to an annular bearing member 86 rigidly secured to'the sleeve 70 by means of a screw 88 and bearing between the sleeve and the chuck spindle 58 axially displaceable therein. The sleeve is further down wardly shaped with an external thread 90 adapted to receive two nuts 92, 94 to adjust and fix the position of the part 72 relative the balls 78. This last-mentioned part is further guided axially relative the other part 70 of the annular member 68 by means of a pin 96 extending into and 'slidable in a groove 98 in part 70. Between the head 66 of the chuck spindle and the annular bearing member 86 the spindle is surrounded by a helical spring 100 by which a chuck 1.02 is kept in the position shown in Fig. 1 relative to the member 68.

When using the device described above in a thread cuttingoperation the positions of the hoods 16 and 66 relative one another is first adjusted so as to provide exer tion'of a suitable pressure on the torque transmitting balls- 46. This pressure should be adjusted so as to ensure that the balls are kept in therecesses 44 during the threadcut ting operation proper, but also so that .as soon as the threading tool reaches the bottomzof the roughly. boredhole, they will roll along the races 45 between 'saidzre cesses. Advantageously the value of the pressure exerted 16 and 24. When the threading tool engages the top end of..th;hole.to be, provided with the thread, the pressure eausediby'said engagement is absorbed by a resilient connection comprisingra rodz104 projecting into an axially extending bore. inithe spindle'10 and abutting at one of itscnds vagainsta spring 106 located in said bore and at its other end against, the head 66 of the chuck spindle 58. Inorder to guide the rod 104 a bearing 108 is provided in the bore of thespindle, said bearing being supplied with lubricant through. a. channel 110 connected with said bore and sealed by a plug 120. When screwing the threading tool down into the roughly bored hole by carrying the entiredevice downwardly, the transmission of the torque from the. spindle is performed, as already stated, by

the balls 46 to thea'nnular member 38 which in turn transmits the torque by means of the axially extending andradially projecting shoulders 60 to the rollers 62 and consequently the chuck spindle 58. As soon as the threading tool has reached the bottom of r the roughly bored hole, the torque moment is increased so much as to cause the balls .46 to roll along the races 45 thereby producing a rattling noise. The operator is thus enabled to determine when the thread cutting operation is finished and he will then draw .t-he device upwardly. By this movement the rollers. 62 are shifted to slide along the pair of shoulders 84 extending axially on the lower an: nularmember 68. Due to the fact that the ends facing one another of the pairs of shoulders 60 |and 84 are spaced apart for a distance greater than the diameter of the rollers 62, the chuck spindle will have an immediate position of idle running, viz. the period when during the shift the rollers 62 pass through the gap existing between the pairs of shoulders. The member 68 has during the whole operation performed a rotational movement opposite in direction to that of the driving spindle due to the balls 78 mounted in the rotationally stationary -retaining member 80 reversing the direction of movement of the hood 16 when transmitting motion to the annular member 68. When the rollers 62 abut against the pair of shoulders 84, the reverse movement is transmitted to the chuck spindle 58 and the threading tool isthreaded back. As soon as the tool is released from the thread cut, the spring 100 returns all parts of theholder to the position illustrated in Fig: 1. a

While one more or less specific embodiment of the invention has been shown it is to be understood that this is for purpose of illustration only, and that the invention is not to be limited thereby, but its scope is to be determined by the appended claims.

What I claim is:

l. A reversible tool holder comprising a driving component, a driven component, torque transmitting members for transmitting direct drive between said components including coupling members connected to the driven component, and torque transmitting members for transmitting drive in reverse direction between said components including a rotatably mounted reverse drive member operatively connected with said driving component to rotate in the direction opposite that of the driving component, said coupling members being relatively shiftable from a first position engaging the driving component to transmit torque between said components in direct drive relation without axial thrust between the components to a second position engaging said reverse drive member to transmit torque between said components in reverse drive relation without axial thrust between the components.

2. A tool holder as defined in claim 1 in which said driving component andsaid reverse drive member are coaxially mounted and provided with axially extending internal abutmentsbetween which said coupling members are axially shiftable to selectively efiect direct drive or reverse drive.

3. A holder as defined in claim 2 in which the adjacent ends of the abutments of the aligned parts are axially spaced apart by a distance greater than the axial extent of said coupling members, whereby to provide an intermediate neutral position in which the coupling members are in engagement with neither the driving component nor said reverse drivemember.

4. A tool holder as definedin claim 2 in which said coupling members comprise transversely extending roller elements rotatably mounted in said driven component and having projecting ends for rolling engagement with said abutments.

5. A tool holder as defined in claim 1 including spring means for normally holding said coupling members in said first position to effect direct drive.

6. A tool holder as defined in claim 1 in which said driven component comprises a chuck spindle having a direct drive end position, and spring means for yieldably resisting movement of the spindle to said end position from a direct drive position adjacent thereto.

7. In a reversible rotary tool holder, a driving spindle,

a hood-like driving member rigid therewith, an annular torque transmitting member coaxially mounted for rotation relative to said driving member, a plurality of circumferentially spaced bores extending axially through said driving member, a plurality of recesses in said annular member located and spaced to register with said bores, detents located in said bores shaped to enter said recesses while remaining partially in said bores to provide for torque transmission between said members, spring means for resiliently loading said detents to permit retraction thereof from said recesses and release of the torque transmitting connection between said members when the torque load exceeds a predetermined value, and a second hood-like member threaded on said driving member to provide for adjustment of the spring load on said detents.

8. In a reversible rotary tool holder, a driving spindle, a hood-like driving member rigid therewith, an annular torque transmitting member coaxially mounted for rotation relative to said driving member, a plurality of circumferentially spaced bores extending axially through said driving member, a plurality of recesses in said annular member located and spaced to register with said bores, detents located in said bores shaped to enter said recesses while remaining partially in said bores to provide for torque transmission between said members, spring means for resiliently loading said detents to permit retraction thereof from said recesses and release of the torque transmitting connection between said members when the torque load exceeds a predetermined value, said driving member and said torque transmitting member be ing provided with confronting concentric grooves and a plurality of balls located in the race formed by said grooves to hold said members in relatively rotatable and axially fixed relation.

9. A tool holder as defined in claim 1 in which said driving component is provided with two internal axially spaced races for engagement by rows of force transmitting balls and said reverse drive member comprises two coaxially mounted elements each provided with a race adapted to be engaged by the balls of one of said rows, and means for adjusting the position of said elements relative toleach other, to selectively locate the positions of the last mentioned races relative to each other and to said first mentioned races.

7 References Cited in the file of this patent UNITED STATES PATENTS 915,900 Steinle Mar. 23, 1909 996,426 Ray June 27, 1911 2,597,849 Alfrcdeen May 27, 1952 

